The metal sticker sounds good to me. Better than nothing or anything else i can do my self. i guess it will last a good while too :). More fancy options could be saved for future cards with bigger budget i guess.
Thanks for the update/documentation posts again btw. They’ve been my lessons in design, engineering and bringing a product to market. :D
Helped me to have ideas like what if old signs made from aluminium plastic composite sheets where used to make a lightweight portable subwoofer or a light weight, cheap shipping box.... shaving the grams off :) and cheap :)